Liquid crystal displays (LCD) which have advantages of low radiation, compact in size and low energy consumption, are gradually replacing conventional cathode ray tube displays, therefore they are widely used in electronic products such as laptops, personal digital assistants (PDA), flat panel televisions or mobile phones, etc. Conventional liquid crystal displays employ external driver chips to drive the pixels on the panels to display images or pictures. In order to decrease the number of components used and to reduce manufacturing costs, in the recent years, it is gradually developed to have the structures of drive circuits integrated directly on the display panels; for example, the gate on array (GOA) technology is applied to integrate gate driver circuits on a liquid crystal panel.
The gate on array (GOA) technology compares to the conventional chip on flex/film (COF) technology, the manufacturing cost could be reduced, and the bonding process of COF on the gate side could be omitted, so the production capacity could be improved. Therefore, the gate on array (GOA) technology is important for the development of liquid crystal panel in the future.
As shown in FIG. 1, an GOA circuit includes plurality of GOA structure units in cascade, each of GOA structure units drives a corresponding scan line. Each of GOA structure units includes a pull-up control circuit {circle around (1)}, a pull-up circuit {circle around (2)}, a transfer circuit {circle around (3)}, a pull-down circuit {circle around (4)}, a pull-down holding circuit {circle around (5)} and a bootstrapping capacitor {circle around (6)} for boosting the voltage. Wherein, the pull-up control circuit {circle around (1)} is configured to control the turn-on time of the pull-up circuit {circle around (2)} to pre-charge a pre-charge signal Q(N), and connects to the transfer signal transferred by the previous stage GOA structure unit and the gate output signal, the pull-up circuit {circle around (2)}; is configured to pull up the voltage of the gate output signal to control the gate to turn on, the transfer circuit {circle around (3)} is configured to control the signal of the next stage GOA structure unit to turn on or turn off, the pull-down circuit {circle around (4)} is configured to pull down the voltage of Q(N) and G(N) to VSS at the first time to turn off the signal of G(N), the pull-down holding circuit {circle around (5)} is configured to hold the voltage of Q(N) and G(N) on VSS (i.e. negative voltage) and generally has two pull-down holding modules to work alternatively, the bootstrapping capacitor {circle around (6)} is configured to boost the voltage of Q(N) for the second time for improving the output of G(N) of the pull-up circuit.
However, when the GOA circuit abnormally power off, some GOA structure units cannot release the charge of the pre-charge signal in time, as the GOA circuit is power on and power off too fast, since the charge of the pre-charge signal of the previous stage GOA structure unit cannot be released, the gate output signal of the previous stage GOA structure unit will be abnormally high current, so the overcurrent protection will be activated and the GOA circuit cannot be restarted or directly burn the GOA circuit.